// // Copyright (C) 2006-2020 Greg Landrum // // @@ All Rights Reserved @@ // This file is part of the RDKit. // The contents are covered by the terms of the BSD license // which is included in the file license.txt, found at the root // of the RDKit source tree. // #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include namespace RDKit { namespace { void updateSubMolConfs(const ROMol &mol, RWMol &res, boost::dynamic_bitset<> &removedAtoms) { // update conformer information: res.clearConformers(); for (auto citer = mol.beginConformers(); citer != mol.endConformers(); ++citer) { auto *newConf = new Conformer(res.getNumAtoms()); newConf->setId((*citer)->getId()); newConf->set3D((*citer)->is3D()); int aIdx = 0; for (unsigned int i = 0; i < mol.getNumAtoms(); ++i) { if (!removedAtoms[i]) { newConf->setAtomPos(aIdx, (*citer)->getAtomPos(i)); ++aIdx; } } res.addConformer(newConf, false); } } } // namespace ROMol *deleteSubstructs(const ROMol &mol, const ROMol &query, bool onlyFrags, bool useChirality) { auto *res = new RWMol(mol, false); std::vector fgpMatches; std::vector::const_iterator mati; VECT_INT_VECT matches; // all matches on the molecule - list of list of atom ids MatchVectType::const_iterator mi; // do the substructure matching and get the atoms that match the query const bool uniquify = true; const bool recursionPossible = true; SubstructMatch(*res, query, fgpMatches, uniquify, recursionPossible, useChirality); // if didn't find any matches nothing to be done here // simply return a copy of the molecule if (fgpMatches.size() == 0) { return res; } for (mati = fgpMatches.begin(); mati != fgpMatches.end(); mati++) { INT_VECT match; // each match onto the molecule - list of atoms ids for (mi = mati->begin(); mi != mati->end(); mi++) { match.push_back(mi->second); } matches.push_back(match); } // now loop over the list of matches and check if we can delete any of them INT_VECT delList; VECT_INT_VECT_I mxi, fi; if (onlyFrags) { VECT_INT_VECT frags; MolOps::getMolFrags(*res, frags); for (fi = frags.begin(); fi != frags.end(); fi++) { std::sort(fi->begin(), fi->end()); for (mxi = matches.begin(); mxi != matches.end(); mxi++) { std::sort(mxi->begin(), mxi->end()); if ((*fi) == (*mxi)) { INT_VECT tmp; Union((*mxi), delList, tmp); delList = tmp; break; } // end of if we found a matching fragment } // endof loop over matches } // end of loop over fragments } // end of if onlyFrags else { // in this case we want to delete any matches we find // simply loop over the matches and collect the atoms that need to // be removed for (mxi = matches.begin(); mxi != matches.end(); mxi++) { INT_VECT tmp; Union((*mxi), delList, tmp); delList = tmp; } } // now loop over the union list and delete the atoms res->beginBatchEdit(); boost::dynamic_bitset<> removedAtoms(mol.getNumAtoms()); for (auto idx : delList) { removedAtoms.set(idx); res->removeAtom(idx); } res->commitBatchEdit(); // if we removed any atoms, clear the computed properties: if (delList.size()) { updateSubMolConfs(mol, *res, removedAtoms); res->clearComputedProps(true); // update our properties, but allow unhappiness: res->updatePropertyCache(false); } return res; } std::vector replaceSubstructs( const ROMol &mol, const ROMol &query, const ROMol &replacement, bool replaceAll, unsigned int replacementConnectionPoint, bool useChirality) { PRECONDITION(replacementConnectionPoint < replacement.getNumAtoms(), "bad replacementConnectionPoint"); std::vector res; std::vector fgpMatches; boost::dynamic_bitset<> removedAtoms(mol.getNumAtoms()); // do the substructure matching and get the atoms that match the query const bool uniquify = true; const bool recursionPossible = true; SubstructMatch(mol, query, fgpMatches, uniquify, recursionPossible, useChirality); // if we didn't find any matches, there's nothing to be done here // simply return a list with a copy of the starting molecule if (fgpMatches.size() == 0) { res.push_back(ROMOL_SPTR(new ROMol(mol, false))); res[0]->clearComputedProps(false); return res; } INT_VECT delList; // now loop over the list of matches and replace them: for (std::vector::const_iterator mati = fgpMatches.begin(); mati != fgpMatches.end(); mati++) { INT_VECT match; // each match onto the molecule - list of atoms ids for (const auto &mi : *mati) { match.push_back(mi.second); } INT_VECT sortMatch = match; std::sort(sortMatch.begin(), sortMatch.end()); if (!replaceAll || !res.size()) { res.push_back(ROMOL_SPTR(new ROMol(mol, false))); } RWMol *newMol = static_cast(res.rbegin()->get()); // we need a tab to the orig number of atoms because the // new molecule will start numbered above this: int numOrigAtoms = newMol->getNumAtoms(); // Add the atoms and bonds from the replacement: newMol->insertMol(replacement); // loop over the central atom's (the first atom in match) bonds // and duplicate any that connect to the remainder of the molecule: Atom *origAtom = newMol->getAtomWithIdx(match[0]); ROMol::ADJ_ITER nbrIdx, endNbrs; boost::tie(nbrIdx, endNbrs) = newMol->getAtomNeighbors(origAtom); while (nbrIdx != endNbrs) { // we don't want to duplicate any "intra-match" bonds: if (!std::binary_search(sortMatch.begin(), sortMatch.end(), int(*nbrIdx))) { Bond *oBond = newMol->getBondBetweenAtoms(match[0], *nbrIdx); CHECK_INVARIANT(oBond, "required bond not found"); newMol->addBond(numOrigAtoms + replacementConnectionPoint, *nbrIdx, oBond->getBondType()); } nbrIdx++; } if (replaceAll) { // we'll accumulate a list of atoms to be removed: INT_VECT tmp; Union(sortMatch, delList, tmp); delList = tmp; } else { // just delete the atoms now: newMol->beginBatchEdit(); for (auto idx : sortMatch) { removedAtoms.set(idx); newMol->removeAtom(idx); } newMol->commitBatchEdit(); } } if (delList.size()) { if (replaceAll) { // remove the atoms from the delList: auto *newMol = static_cast(res[0].get()); newMol->beginBatchEdit(); for (auto idx : delList) { removedAtoms.set(idx); newMol->removeAtom(idx); } newMol->commitBatchEdit(); } // clear conformers and computed props and do basic updates // on the resulting molecules, but allow unhappiness: for (auto &re : res) { updateSubMolConfs(mol, *(RWMol *)re.get(), removedAtoms); re->clearComputedProps(true); re->updatePropertyCache(false); } } return res; } ROMol *replaceSidechains(const ROMol &mol, const ROMol &coreQuery, bool useChirality) { MatchVectType matchV; // do the substructure matching and get the atoms that match the query const bool recursionPossible = true; bool matchFound = SubstructMatch(mol, coreQuery, matchV, recursionPossible, useChirality); // if we didn't find any matches, there's nothing to be done here // simply return null to indicate the problem if (!matchFound || matchV.size() == 0) { return nullptr; } boost::dynamic_bitset<> matchingIndices(mol.getNumAtoms()); for (MatchVectType::const_iterator mvit = matchV.begin(); mvit != matchV.end(); ++mvit) { matchingIndices[mvit->second] = 1; } auto *newMol = new RWMol(mol); boost::dynamic_bitset<> keepSet(newMol->getNumAtoms()); std::vector dummyIndices; for (MatchVectType::const_iterator mvit = matchV.begin(); mvit != matchV.end(); ++mvit) { keepSet.set(mvit->second); // if the atom in the molecule has higher degree than the atom in the // core, we have an attachment point: if (newMol->getAtomWithIdx(mvit->second)->getDegree() > coreQuery.getAtomWithIdx(mvit->first)->getDegree()) { ROMol::ADJ_ITER nbrIdx, endNbrs; boost::tie(nbrIdx, endNbrs) = newMol->getAtomNeighbors(newMol->getAtomWithIdx(mvit->second)); while (nbrIdx != endNbrs) { if (!matchingIndices[*nbrIdx]) { // this neighbor isn't in the match, convert it to a dummy atom and // save it keepSet.set(*nbrIdx); dummyIndices.push_back(*nbrIdx); Atom *at = newMol->getAtomWithIdx(*nbrIdx); Bond *b = newMol->getBondBetweenAtoms(mvit->second, *nbrIdx); if (b) { b->setIsAromatic(false); b->setBondType(Bond::SINGLE); } at->setAtomicNum(0); at->setNumExplicitHs(0); at->setIsAromatic(false); at->setIsotope(dummyIndices.size()); } ++nbrIdx; } } } boost::dynamic_bitset<> removedAtoms(mol.getNumAtoms()); newMol->beginBatchEdit(); for (const auto at : newMol->atoms()) { if (!keepSet.test(at->getIdx())) { newMol->removeAtom(at); removedAtoms.set(at->getIdx()); } } // Remove bonds between newly added dummies (if any) if (dummyIndices.size() > 1) { for (size_t i = 0; i < dummyIndices.size() - 1; ++i) { for (size_t j = i + 1; j < dummyIndices.size(); ++j) { const auto b = newMol->getBondBetweenAtoms(dummyIndices.at(i), dummyIndices.at(j)); if (b) { newMol->removeBond(dummyIndices.at(i), dummyIndices.at(j)); } } } } newMol->commitBatchEdit(); updateSubMolConfs(mol, *newMol, removedAtoms); // clear computed props and do basic updates on the // the resulting molecule, but allow unhappiness: newMol->clearComputedProps(true); newMol->updatePropertyCache(false); return static_cast(newMol); } ROMol *replaceCore(const ROMol &mol, const ROMol &coreQuery, bool replaceDummies, bool labelByIndex, bool requireDummyMatch, bool useChirality) { MatchVectType matchV; // do the substructure matching and get the atoms that match the query const bool recursionPossible = true; bool matchFound = SubstructMatch(mol, coreQuery, matchV, recursionPossible, useChirality); // if we didn't find any matches, there's nothing to be done here // simply return null to indicate the problem if (!matchFound || matchV.size() == 0) { return nullptr; } return replaceCore(mol, coreQuery, matchV, replaceDummies, labelByIndex, requireDummyMatch); } ROMol *replaceCore(const ROMol &mol, const ROMol &core, const MatchVectType &matchV, bool replaceDummies, bool labelByIndex, bool requireDummyMatch) { unsigned int origNumAtoms = mol.getNumAtoms(); std::vector matchingIndices(origNumAtoms, -1); std::vector allIndices(origNumAtoms, -1); for (const auto &mvit : matchV) { if (mvit.first < 0 || mvit.first >= rdcast(core.getNumAtoms())) { throw ValueErrorException( "Supplied MatchVect indices out of bounds of the core molecule"); } if (mvit.second < 0 || mvit.second >= rdcast(mol.getNumAtoms())) { throw ValueErrorException( "Supplied MatchVect indices out of bounds of the target molecule"); } if (replaceDummies || core.getAtomWithIdx(mvit.first)->getAtomicNum() > 0) { matchingIndices[mvit.second] = mvit.first; } allIndices[mvit.second] = mvit.first; } auto *newMol = new RWMol(mol); std::vector keepList; std::map dummyAtomMap; // go through the matches in query order, not target molecule // order std::vector> matchorder_atomidx; for (unsigned int i = 0; i < origNumAtoms; ++i) { int queryatom = allIndices[i]; matchorder_atomidx.emplace_back(queryatom, i); } std::sort(matchorder_atomidx.begin(), matchorder_atomidx.end()); std::vector> dummies; for (unsigned int j = 0; j < origNumAtoms; ++j) { auto i = (unsigned)matchorder_atomidx[j].second; if (matchingIndices[i] == -1) { Atom *sidechainAtom = newMol->getAtomWithIdx(i); // we're keeping the sidechain atoms: keepList.push_back(sidechainAtom); int mapping = -1; // if we were not in the matching list, still keep // the original indices (replaceDummies=False) if (allIndices[i] != -1) { mapping = allIndices[i]; } // loop over our neighbors and see if any are in the match: std::list nbrList; ROMol::ADJ_ITER nbrIter, endNbrs; boost::tie(nbrIter, endNbrs) = newMol->getAtomNeighbors(sidechainAtom); while (nbrIter != endNbrs && (*nbrIter) < origNumAtoms) { // we need to add bonds and atoms to the molecule while looping // over neighbors. This invalidates iterators, so collect a list // of our neighbors now: nbrList.push_back(*nbrIter); ++nbrIter; } unsigned int whichNbr = 0; std::list newBonds; for (std::list::const_iterator lIter = nbrList.begin(); lIter != nbrList.end(); ++lIter) { unsigned int nbrIdx = *lIter; Bond *connectingBond = newMol->getBondBetweenAtoms(i, nbrIdx); if (matchingIndices[nbrIdx] > -1) { // we've matched an atom in the core. if (requireDummyMatch && core.getAtomWithIdx(matchingIndices[nbrIdx])->getAtomicNum() != 0) { delete newMol; return nullptr; } auto *newAt = new Atom(0); // we want to order the dummies int the same orders as // the mappings, if not labelling by Index they are in arbitrary // order // right now so save and sort later. if (mapping != -1) { dummies.emplace_back(mapping, newAt); } else { dummies.emplace_back(matchingIndices[nbrIdx], newAt); } newMol->addAtom(newAt, false, true); dummyAtomMap[nbrIdx] = newAt; keepList.push_back(newAt); Bond *bnd = connectingBond->copy(); if (bnd->getBeginAtomIdx() == i) { bnd->setEndAtomIdx(newAt->getIdx()); } else { bnd->setBeginAtomIdx(newAt->getIdx()); } newBonds.push_back(bnd); // we may be changing the bond ordering at the atom. // e.g. replacing the N in C[C@](Cl)(N)F gives an atom ordering of // C[C?](Cl)(F)[X] // so we need the SMILES C[C@@](Cl)(F)[X] to maintain the appropriate // chirality // check for these cases and adjust our chirality flags as // appropriate. // if (sidechainAtom->getChiralTag() == Atom::CHI_TETRAHEDRAL_CW || sidechainAtom->getChiralTag() == Atom::CHI_TETRAHEDRAL_CCW) { bool switchIt = false; switch (newMol->getAtomDegree(sidechainAtom)) { case 4: // start: ordering: swap? // N[C@](F)(Cl)C -> F[C@@](Cl)(C)X yes // F[C@](N)(Cl)C -> F[C@](Cl)(C)X no // F[C@](Cl)(N)C -> F[C@@](Cl)(C)X yes // F[C@](Cl)(C)N -> F[C@](Cl)(C)X no if (!(whichNbr % 2)) { switchIt = true; } break; case 3: // things are different in the degree three case because of the // implicit H: // start: ordering: swap? // N[C@H](F)C -> [C@H](F)(C)X yes // [C@H](N)(F)C -> [C@H](F)(C)X no // F[C@H](N)C -> F[C@@H](C)X yes // F[C@H](C)N -> F[C@H](C)X no if (whichNbr == 1) { switchIt = true; } break; } if (switchIt) { sidechainAtom->invertChirality(); } } } ++whichNbr; } // add the bonds now, after we've finished the loop over neighbors: for (auto &newBond : newBonds) { newMol->addBond(newBond, true); auto beginAtom = newBond->getBeginAtom(); auto endAtom = newBond->getEndAtom(); if (newMol->getNumConformers()) { if (endAtom->getAtomicNum() == 0) { MolOps::setTerminalAtomCoords(*newMol, endAtom->getIdx(), beginAtom->getIdx()); } else { MolOps::setTerminalAtomCoords(*newMol, beginAtom->getIdx(), endAtom->getIdx()); } } } } } if (!labelByIndex) { // sort the mapping indices, but label from 1..N std::stable_sort(dummies.begin(), dummies.end()); for (size_t nDummy = 0; nDummy < dummies.size(); ++nDummy) { dummies[nDummy].second->setIsotope(nDummy + 1); } } else { // don't sort, just label by the index for (auto &dummy : dummies) { dummy.second->setIsotope(dummy.first); } } std::vector delList; boost::dynamic_bitset<> removedAtoms(mol.getNumAtoms()); newMol->beginBatchEdit(); for (const auto at : newMol->atoms()) { if (std::find(keepList.begin(), keepList.end(), at) == keepList.end()) { newMol->removeAtom(at); removedAtoms.set(at->getIdx()); } } newMol->commitBatchEdit(); updateSubMolConfs(mol, *newMol, removedAtoms); // make a guess at the position of the dummy atoms showing the attachment // point: for (auto citer = mol.beginConformers(); citer != mol.endConformers(); ++citer) { Conformer &newConf = newMol->getConformer((*citer)->getId()); for (std::map::const_iterator iter = dummyAtomMap.begin(); iter != dummyAtomMap.end(); ++iter) { newConf.setAtomPos(iter->second->getIdx(), (*citer)->getAtomPos(iter->first)); } } // clear computed props and do basic updates on // the resulting molecule, but allow unhappiness: newMol->clearComputedProps(true); newMol->updatePropertyCache(false); return static_cast(newMol); } ROMol *MurckoDecompose(const ROMol &mol) { auto *res = new RWMol(mol); unsigned int nAtoms = res->getNumAtoms(); if (!nAtoms) { return res; } // start by getting the shortest paths matrix: MolOps::getDistanceMat(mol, false, false, true); boost::shared_array pathMat; mol.getProp(common_properties::DistanceMatrix_Paths, pathMat); boost::dynamic_bitset<> keepAtoms(nAtoms); const RingInfo *ringInfo = res->getRingInfo(); for (unsigned int i = 0; i < nAtoms; ++i) { if (ringInfo->numAtomRings(i)) { keepAtoms[i] = 1; } } const VECT_INT_VECT &rings = ringInfo->atomRings(); // std::cerr<<" rings: "< "< removedAtoms(nAtoms); res->beginBatchEdit(); for (unsigned int i = 0; i < nAtoms; ++i) { if (!keepAtoms[i]) { Atom *atom = res->getAtomWithIdx(i); bool removeIt = true; // check if the atom has a neighboring keeper: ROMol::ADJ_ITER nbrIdx, endNbrs; boost::tie(nbrIdx, endNbrs) = res->getAtomNeighbors(atom); while (nbrIdx != endNbrs) { Atom *nbr = (*res)[*nbrIdx]; if (keepAtoms[nbr->getIdx()]) { if (res->getBondBetweenAtoms(atom->getIdx(), nbr->getIdx()) ->getBondType() == Bond::DOUBLE) { removeIt = false; break; } else if (nbr->getIsAromatic() && nbr->getAtomicNum() != 6) { // fix aromatic heteroatoms: nbr->setNumExplicitHs(1); } else if (nbr->getIsAromatic() && nbr->getAtomicNum() == 6 && nbr->getFormalCharge() == 1) { // fix aromatic carbocations nbr->setNumExplicitHs(1); } else if (nbr->getNoImplicit() || nbr->getChiralTag() != Atom::CHI_UNSPECIFIED) { nbr->setNoImplicit(false); nbr->setNumExplicitHs(0); nbr->setChiralTag(Atom::CHI_UNSPECIFIED); } } ++nbrIdx; } if (removeIt) { res->removeAtom(atom); removedAtoms.set(atom->getIdx()); } } } res->commitBatchEdit(); updateSubMolConfs(mol, *res, removedAtoms); res->clearComputedProps(); return (ROMol *)res; } ROMol *combineMols(const ROMol &mol1, const ROMol &mol2, RDGeom::Point3D offset) { auto *res = new RWMol(mol1); int nAtoms1 = res->getNumAtoms(); res->insertMol(mol2); // copy over coordinates if (mol1.getNumConformers() && mol2.getNumConformers()) { if (mol1.getNumConformers() != mol2.getNumConformers()) { BOOST_LOG(rdWarningLog) << "combineMols: molecules have unequal numbers of conformers" << std::endl; } for (auto conf1It = res->beginConformers(); conf1It != res->endConformers(); ++conf1It) { Conformer *conf1 = (*conf1It).get(); try { const Conformer *conf2 = &mol2.getConformer(conf1->getId()); for (unsigned int i = 0; i < mol2.getNumAtoms(); ++i) { conf1->setAtomPos(i + nAtoms1, conf2->getAtomPos(i) + offset); } } catch (ConformerException &) { BOOST_LOG(rdWarningLog) << "combineMols: conformer id " << conf1->getId() << " not found in mol2"; } } } res->clearComputedProps(true); return (ROMol *)res; } void addRecursiveQueries( ROMol &mol, const std::map &queries, const std::string &propName, std::vector> *reactantLabels) { std::string delim = ","; boost::char_separator sep(delim.c_str()); if (reactantLabels != nullptr) { (*reactantLabels).resize(0); } ROMol::VERTEX_ITER atBegin, atEnd; boost::tie(atBegin, atEnd) = mol.getVertices(); while (atBegin != atEnd) { Atom *at = mol[*atBegin]; ++atBegin; if (!at->hasProp(propName)) { continue; } std::string pval; at->getProp(propName, pval); std::string maybeSmarts = pval; // keep unmodified in case we are a smarts string boost::algorithm::to_lower(pval); if (reactantLabels != nullptr) { std::pair label(at->getIdx(), pval); (*reactantLabels).push_back(label); } QueryAtom::QUERYATOM_QUERY *qToAdd = nullptr; bool notFound = false; if (pval.find(delim) != std::string::npos) { boost::tokenizer> tokens(pval, sep); boost::tokenizer>::iterator token; qToAdd = new ATOM_OR_QUERY(); qToAdd->setDescription("AtomOr"); for (token = tokens.begin(); token != tokens.end(); ++token) { auto iter = queries.find(*token); if (iter == queries.end()) { delete qToAdd; notFound = true; break; } auto *tqp = new RecursiveStructureQuery(new ROMol(*(iter->second))); std::shared_ptr nq(tqp); qToAdd->addChild(nq); } } else { auto iter = queries.find(pval); if (iter == queries.end()) { notFound = true; } else { qToAdd = new RecursiveStructureQuery(new ROMol(*(iter->second))); } } if (notFound) { // See if we are actually a smarts expression already RWMol *m = nullptr; try { m = SmartsToMol(maybeSmarts); if (!m) { throw KeyErrorException(pval); } qToAdd = new RecursiveStructureQuery(m); } catch (...) { throw KeyErrorException(pval); } } if (!at->hasQuery()) { QueryAtom qAt(*at); unsigned int idx = at->getIdx(); static_cast(mol).replaceAtom(idx, &qAt); at = mol.getAtomWithIdx(idx); } at->expandQuery(qToAdd, Queries::COMPOSITE_AND); } } void parseQueryDefFile(std::istream *inStream, std::map &queryDefs, bool standardize, const std::string &delimiter, const std::string &comment, unsigned int nameColumn, unsigned int smartsColumn) { PRECONDITION(inStream, "no stream"); queryDefs.clear(); boost::char_separator sep(delimiter.c_str()); unsigned int line = 0; std::string tempStr; while (!inStream->eof() && !inStream->fail()) { line++; tempStr = getLine(inStream); if (tempStr == "" || tempStr.find(comment) == 0) { continue; } boost::tokenizer> tokens(tempStr, sep); unsigned int tpos; boost::tokenizer>::iterator token; std::string qname = ""; std::string qval = ""; for (token = tokens.begin(), tpos = 0; token != tokens.end(); ++token, ++tpos) { if (tpos == nameColumn) { qname = *token; } else if (tpos == smartsColumn) { qval = *token; } } boost::trim_if(qname, boost::is_any_of(" \t")); boost::trim_if(qval, boost::is_any_of(" \t")); if (qname == "" || qval == "") { continue; } RWMol *m = nullptr; try { m = SmartsToMol(qval); } catch (...) { m = nullptr; } if (!m) { BOOST_LOG(rdWarningLog) << "cannot convert SMARTS " << qval << " to molecule at line " << line << std::endl; continue; } ROMOL_SPTR msptr(m); if (standardize) { boost::algorithm::to_lower(qname); } queryDefs[qname] = msptr; } } void parseQueryDefFile(const std::string &filename, std::map &queryDefs, bool standardize, const std::string &delimiter, const std::string &comment, unsigned int nameColumn, unsigned int smartsColumn) { std::ifstream inStream(filename.c_str()); if (!inStream || (inStream.bad())) { std::ostringstream errout; errout << "Bad input file " << filename; throw BadFileException(errout.str()); } parseQueryDefFile(&inStream, queryDefs, standardize, delimiter, comment, nameColumn, smartsColumn); } void parseQueryDefText(const std::string &queryDefText, std::map &queryDefs, bool standardize, const std::string &delimiter, const std::string &comment, unsigned int nameColumn, unsigned int smartsColumn) { std::stringstream inStream(queryDefText); parseQueryDefFile(&inStream, queryDefs, standardize, delimiter, comment, nameColumn, smartsColumn); } } // end of namespace RDKit